Section No. 14-2. The intensity of electrical energy

Blame it on the loss of electrical energy

The power of electrical energy, indicators and the most common causes of the decrease in the power of electrical energy induced in Table 1:

Table 1. Power of electrical energy, indicators and the greatest causes of loss of energy your electrical energy.

Power of the electric	Indicator KE				The most popular
					blame for the loss of KE
					Energopostachalna
Voltage recovery	Vidhilennya, which has become tense,
	nya δU y				organization
					Spozhivach z
Voltage voltage	Voltage range U t
	Pt flicker dose				changeable obsessions
					Spozhivach z
Non-sinusoidality	Coefficient	confusion
	consistency of the curve		voltage K v		nonlinear interests
	Coefficient of n-th harmonic
	storage voltage K U(i)
					Spozhivach s asymmetrical
Asymmetry	Coefficient		asymmetry
three-phase system	voltage			gateway	river navantazhennyam
voltage	sequence K 2U Coefficient
	voltage asymmetry beyond zero
	sequence K 0U
					Energopostachalna
Frequency infusion	Frequency change ∆f
					organization
					Energopostachalna
Voltage failure	Trivality of voltage failure ∆t p
					organization
					Energopostachalna
Voltage impulse	Pulse voltage U imp
					organization
					Energopostachalna
Timchasov	Hourly coefficient
overvoltage	overvoltageK perU				organization

Types of electrical interconnection systems of electrical supply for general purposes include electrical receivers for various purposes, let's look at industrial electrical receivers.

The most typical types of electric primers that are widely used in various industries are electric motors and electric lighting installations. A significant increase in the knowledge of electrothermal installations, and

valve switches, which serve to convert the exchangeable stream into a stationary one. The steady stream at industrial enterprises is stagnated for the life of engines of the stationary stream, electrolysis, in galvanic processes, in various types of welding, etc.

Electric lighting installations with frying lamps, fluorescent lamps, arc lamps, mercury lamps, sodium lamps, xenon lamps are installed at all enterprises for internal and external lighting, and the needs of public lighting etc. . Roaster lamps are characterized by nominal parameters: high intensity P nom, light flux

F nom, light output η nom (equal ratio of the light flux produced by the lamp to its intensity) and the average nominal service term T nom. These indicators should significantly lie under the voltage at the terminals of the frying lamps. Voltage changes lead to consistent changes in light flow and brightness, which, in turn, affects the productivity and fatigue of people.

Due to the specificity of their regulation, valve converters are associated with reactive pressure (the pressure coefficient of valve converter rolling mills ranges from 0.3 to 0.8), which influences the voltage reduction value ugh in the midst of life. Start by installing the automatic regulation system of the steady flow with the help of phase control. When the voltage rises during the period, the regulation automatically increases, and when the voltage decreases, it changes. A 1% increase in tension results in an increase in reactive tension by approximately 1-1.4%, which leads to a decrease in the tension coefficient. More harmonics of the voltage and flow unfavorably flow into electrical installations, automation systems, relay protection, telemechanics and connections. There are additional costs in electrical machines, transformers and circuits, compensation of reactive load using capacitor banks is becoming more difficult, and the insulation service life of electrical machines is shortening. Non-sinusoidality coefficient

during the operation of thyristor reversing rolling mills, values ​​of more than 30% can be reached on the 10 kV side of the life voltage; due to the symmetry of their voltage, the valve reversing devices do not affect the symmetry of the voltage.

Electrical installations can cause damage to the normal working minds of other electrical workers. Chemical welding units, the power of which currently reaches 1500 kW per unit, generate significantly higher voltage fluctuations in electrical circuits, for example, the launch of asynchronous motors with a squirrel-cage rotor. In addition, the voltage is generated over a wide frequency range, including a range that is unacceptable for electrical lighting installations (about 10 Hz). Electrical welding installations of alternating jet arc and contact welding are single-phase uneven and non-sinusoidal welding with a low force coefficient: 0.3 for arc welding and 0.7 for contact. Welding transformers and low-voltage devices are connected to a level of 380/220 V, heavy-duty ones – to a level of 6 – 10 kV.

Electrothermal installations should be divided into groups based on the heating method: arc furnaces, direct and indirect support furnaces, electronic melting furnaces, vacuum, slag remelting, induction furnaces. This group of electricians also interferes with life, for example, arc furnaces, which can output up to 10 MW, are currently operating as single-phase. This leads to disruption of the symmetry of the flow and tension. In addition, the stench leads to a non-sinusoidality of the streams, and, therefore, tension.

The main sources of electricity in industrial enterprises are asynchronous electric motors. The increase in voltage within the permissible norms affects the frequency of their cooking, consumption of active and reactive mass (voltage reduction by 19%

nominal increase in active effort expenditure by 3%; An increase in tension by 1% leads to an increase in the level of reactive tension by 3%). There is a clear distinction between the asymmetrical and symmetrical modes. Of particular importance is the voltage of the turning sequence. The support of the reversible sequence of electric motors is approximately the same as the support of a galvanized motor and, therefore, 5-8 times smaller than the support of the direct sequence. Therefore, the slight asymmetry of the voltage produces significant flows of the return sequence. The jets of the reverse sequence are superimposed on the jets of the direct sequence and cause additional heating of the stator and rotor (especially the massive parts of the rotor), which leads to accelerated insulation and a change in the tension of the engine, which tashovuєstsya. Thus, the service life of a permanently installed asynchronous motor, which operates at a voltage unbalance of 4%, shortens twice.

Methods and methods for reducing the amount of electrical energy

The type of PKE can be achieved by GOST by circuit solutions or by using special technical features. The choice of these values ​​is based on the basis of technical and economical processing, in which the task is not to minimize the overflows, but rather to determine the DSTU.

To enhance all PCs, it is necessary to completely connect electrical receivers with simplified operating modes to the EEC points with the highest values ​​of short-circuit intensity. When choosing power supply schemes, ensure the interchange of short-circuit struts of the optimal level with the required displacement of the PKE.

To reduce the surge in the “quiet” demand of valve electrical actuators and the sharp change in demand, the connections of such actuators should be connected to the adjacent sections of the busbar duct of the substation with transformers with split winding or two These reactors.

Possibility of redness of the skin PKE.

1. Ways to reduce the frequency range:

1.1 increased strength of the short circuit at the point of receiving the signals from sharply changing and “calm” pressure;

1.2 provision of sharply variable and “calm” stimulation through the edges of split windings of transformers.

2. Enter to maintain voltage levels within acceptable limits:

2.1. It is rational to use the SES way to supply the moved voltage for the lines to maintain business; vikoristannya of deep inputs; optimal use of transformers; The lining of the jet ducts at the separate edges has been lined.

2.2. Vikoristannya jumper for voltage up to 1 kV between workshops

2.3 Reducing the internal support of the SES enterprise to the parallel operation of the GPP transformers, so that short-circuit currents do not exceed the permissible values ​​for switching-dry equipment.

2.4 Regulates the voltage of power generator generators.

2.5 Improvement of the regulatory capabilities of synchronous motors using automatic activation control (AEC).

2.6 Installs autotransformers and voltage regulation devices (OLTC) in power double-winding transformers.

2.7 The stagnation of structures must be compensated for.

3. Reduced voltage can be reached via the following route:

3.1 For double reactors, the strength of the sharply variable voltage that can be connected to one reactor head indicates

behind the Wisłowa	S р.н =			δU t			De d U t	− voltage variation
			u short circuit		50x in
			S n.t.		U n 2

on busbars connected to one head of the reactor during an hour of operation of a sharp changeable pressure connected to another head; u short circuit −

short-circuit voltage of the transformer, before connecting the double reactor; S n.t. − nominal tension of the transformer; x in – support of the reactor head; U n −

nominal voltage voltage.

3.2 transformers with a split winding, the maximum tension of a sharply variable voltage connected to one winding is calculated using the formula S р.н. = 0.8 S b.t. δ U t.

3.3 installation of flexible static compensating devices.

4. Ways to deal with high harmonics:

4.1 Increased number of rectifier phases.

4.2 Installation of filters or filter-compensating devices.

5. Methods to combat asymmetry (which does not require the installation of special devices):

5.1 Uniform distribution of single-phase vantagens by phases.

5.2 Connection of asymmetrical connections to sections of the fence with greater short-circuit tension or increased short-circuit tension.

5.3 Vision of asymmetrical applications around transformers.

5.4 A selection of special techniques to reduce asymmetry: 5.4.1 Replacing transformers with a winding connection circuit Y - Y 0

on transformers with a connection circuit ∆ - Y 0 (at boundaries up to

1 kV). When the zero-sequence currents, multiples of three, short-circuit at the first winding, the system is equally important, and the zero-sequence supports sharply

changes.

5.4.2 Because The 6-10 kV lines are connected depending on the insulated neutral, the reduction of asymmetrical storage is achieved by stagnant capacitor banks (victorized for lateral compensation), which are included in the asymmetrical or non-symmetrical circuit. In this case, the distribution of the total tension of the BC between the phases of the measure is drawn in such a way that the flow of the turning sequence that is created is close to the values ​​of the turning sequence of the desired effect.

5.4.3 An effective method is the use of non-regulated devices, for example, a symmetrical device for single-phase actuators, based on Steinmetz circuits.

If Z n = R n, then

		simultaneous bath
it's coming				Vikonanny
Q L = Q C =				de R n
active				tightness
Simulation scheme
navantazhennya.
single-phase navantazhenya
			R n + j ωL ,
Steinmettsa				avantaged
in parallel
connect the bookmaker, as on
				shown
dotted line

Power supply

This document is divided into the project of divisions on the basis of the “Information Sheet - Attachment IP-22/99” and is consistent with the Russian Law “On the Protection of the Rights of Livestock” (Article 7) and the Decree of the Russian Federation dated September 13, 1997 . No. 1013 Electrical energy is a product and is subject to obligatory certification for the indicators of luminosity established by GOST 131-9-97 “Norms for the luminosity of electrical energy in electrical power supply systems.”

The quality of electrical energy is subject to the “Rules for Certification of Electrical Energy” and must comply with 6 main points:

1 - relieve the tension that has risen;
2 different frequencies;
3- coefficient of transformation of the sinusoidal shape of the voltage curve;
4-factor n-noy harmonic storage voltage;
5 coefficient of voltage asymmetry according to the turning sequence;
6 coefficient of voltage asymmetry according to zero sequence.

Voltage recovery characterized by an indicator of stress relief, for which the established norms are:

The normally permissible and limiting permissible values ​​of the voltage at the terminals of electrical energy sources are approximately 5% and 10% of the rated voltage of the electrical current.

Normally permissible and limiting permissible values ​​of voltage at the points of external supply of residential electrical energy up to an electrical voltage of 0.38 kV and more, as established in contracts for the supply of electrical energy Between energy-saving organization and life.

Voltage frequency variation characterized by a display of vigilance, for which the following standards are established:

The normally permissible and limiting permissible values ​​of frequency variation are 0.2 and 0.4 Hz in general.

Sinusoidality coefficient The voltage curve for normal mode should be 0.38 kV -8%, for 6-10 kV -5%, the maximum permissible values ​​are 12% and 8%.

Coefficient of p-noy harmonious warehouse The voltage at the points of connection to the electrical boundaries with different nominal voltages is indicated in Table 2 of GOST 13109-97.

Voltage imbalance characterized by the following indicators:

voltage asymmetry coefficient according to the turning sequence;
voltage asymmetry coefficient beyond zero sequence.

The normally permissible and limiting permissible values ​​of the voltage asymmetry coefficient along the return sequence at the points of the frontal connection to the electrical level reach 2.0 and 4.0%, respectively.

2.1. Indicators of electricity consumption and their regulation

For a long time, the development of energy in our region has been accompanied by an underestimation and often ignoring of the problems of electrical energy, which has led to a massive destruction of the electromagnetic capacity of electrical circuits, living together Nergosystem. Electromagnetic resistance is defined as the ability of an electrical device to function satisfactorily in an electromagnetic environment in which other devices are located. The electrical energy of the rivers in the rivers is dwindling, so their reductions can increase. Nina has developed a complex situation with a lot of technological processes, for example, biotechnologies, automatic lines, computing, vacuum, microprocessor technology, telemechanics, electrical systems, etc. The natural source of electrical energy can no longer be reliably (without being damaged).

When the time has come, it is necessary to consider electrical energy (EE) as a commodity that, in any system of government, is characterized by distinct (specific) characteristics, the flow and meaning of which indicate its survivable power.

Energy supply (KE) There is a clear totality of parameters that describe the peculiarities of the transmission process for its use in normal operation, meaning the uninterrupted power supply (including the number of trivial and short-term interruptions in electrical current) it characterizes the voltage (magnitude, asymmetry, frequency, shape of the voltage). To this end, we add two more respects.

First of all: KE as a whole is expressed by the level of satisfaction with electrical power supply, which is important from a practical point of view.

In other words: KE lies not only in the minds of electrical power supply, but also in the features of electrical equipment that are subject to change (its criticality to electromagnetic transients (EMP), as well as the possibility of their generation) and operating practices. The remaining respect is due to the fact that the responsibility for EC is not only the organization that supplies electricity, but also the supply of electricity and electricity generators.

The International Electrotechnical Commission (IEC) develops and confirms the EEC standards of three types: initially, which includes a description of the electromagnetic medium, terminology, expressions and equal boundaries generation of EMF and testing of features for determining indicators of electrical energy capacity (PKE), recommendations for the preparation of electrical equipment; underground standards, which establish acceptable levels of EMP, which are generated or their acceptable levels in electrical lines for household and industrial purposes; detailed (subject) norms that apply benefits to a wide variety of devices and devices from the perspective of KE.

The main organization in Europe that coordinates the work for standardization in electrical engineering, electronics and related products is known to the MEK. It is necessary to name such international organizations as the Committee of Great Electrical Systems and the Assembly of Manufacturers and Distributors. The most important regional organization that deals with normalization in the EU for the European Union (EU) is CENELEC. There are still very few international professional organizations and national committees that develop national standards for CE, usually based on IEC standards. The praise for the norms is determined, by the head rank, by the method of expert assessments by the voting process.

The normalization of the PKE value is based on the main nutritional problems of the KE. The PKE system is determined by a number of characteristics of large (voltage) and rapid (variable) changes in the voltage value, its shape and symmetry in a three-phase system, as well as frequency changes. The personnel of energy services of enterprises cannot keep up with the frequency of the measure. The blame arises from the appearance of food from autonomous devices, which practically occur very rarely. Therefore, they are looking at the lack of food, so that they can stay up to KE with enough tension.

The principles of standardization of PKE for voltage are based on technical and economic changes and adhere to the current ones:

Voltage PKEs have energy values ​​that characterize the strength (energy) of the voltage curve, the level of negative impact of energy on electrical installations, and the efficiency of technological processes is equal there are significant values ​​for the PKE;

The limiting permissible values ​​of PKE are determined from technical and economic considerations;

PKE is normalized with a given reliability over a period of time to determine specific values ​​that allow setting.

p align="justify"> The PKE system, which is based on many changes of mind, may begin to stagnate from design work. It allows you to achieve mass metrological security of control of CE using many simple and inexpensive devices, as well as implement approaches and technical means of normalizing CE.

In Ukraine, since 1 June 2000, the interstate standard GOST 13109-97 “Standards of electrical energy capacity in electrical power systems for external purposes” has been introduced into force. The standard establishes the indicators and norms of KE in the electrical connections of electrical power supply systems of alternating triphase and single-phase current with a frequency of 50 Hz at units that include electrical connections that are in the hands of the authorities of various associates, and bo priymachi ЇЇ (at the universities of zagalnogo priєdnannya). For the implementation of the established norms, the electromagnetic integrity of the electrical connections of electrical supply systems for external purposes and the electrical connections of co-operators (priymachiv ЇЇ) will be ensured.

The standards established by the designated standard are mandatory for all modes of operation of electrical power supply systems for external purposes, except for modes such as:

Vinyatkov’s weather brains and elemental hardships (hurricane, storm, earth-truck, etc.);

Non-transferable situations, such as conflicts with the actions of the parties, which is not an energy-sustaining organization and a living one (pozhezha, vibukh, military actions, etc.);

Minds, which are regulated by state governing bodies, as well as those associated with the liquidation of inheritances caused by blameless weather minds and non-transferable furnishings.

The norms established by this standard encourage the inclusion of technical minds in the acquisition of companions and contracts for the supply of electricity between electricity supply companies and companions. Conformed to GOST 13109-97 with indicators KE є:

Voltage control dU;

Voltage range dUt;

Pt flicker dose;

Coefficient of saturation of the sinusoidality of the voltage curve KU;

Coefficient of n-th harmonic storage voltage KU (n);

Voltage unbalance factor according to the return sequence K 2U;

Voltage asymmetry coefficient according to zero sequence K 0U;

Frequency improvement (f;

Trouble with voltage failure Dtn;

Impulse voltage U imp;

Time-hour overvoltage coefficient K perU.

It should be noted that there are two types of norms on KE – normally acceptable and marginally acceptable. The assessment of PC compliance with the established standards is carried out throughout the growth period, which dates back to 24 years.

Most objects that are kept in electrical circuits and are exposed to electrical energy are related to the peculiarities of the robotic operation of electrical acceptors and electrical circuits. electromagnetic properties. In this case, it is important to consider the costs (losses) of voltage in the electrical circuit where residents live.

The voltage consumption on the electrical circuit is indicated as follows:

The active (R) and reactive (X) support of the plot of the fence is indicated here to be stable, and the active (P) and reactive (Q) tensions that are transmitted by the plot of the fence are changeable. The nature of these changes may also be different, which results in different values ​​of voltage consumption:

In case of further changes, the appointment will be carried out according to your schedule – stress relief;

With a sharply changeable nature of vantage - voltage level;

With an asymmetrical distribution of voltage behind the phases of the electrical circuit – voltage asymmetry in a three-phase system;

With nonlinear vantagement – non-sinusoidal shape of the vantage curve.

In the case of such objects, which cannot generate electrical energy, you are deprived of the ability to protect your possessions with special means, for example, devices for automatic protection or devices for guaranteed life.

The responsibility for maintaining voltage within the limits established by GOST 13109-97 rests with the energy supply organization.

Voltage recovery (VN) – The actual voltage in the steady-state operating mode of the electrical supply system is inconsistent with the nominal value. It is characterized by a significant improvement in the indicator of stable VN dU.

Voltage relief at this and other points of the boundary is observed, as indicated, under the influx of a large change in pressure according to its schedule.

GOST 13109 - 97 installs permissible values ​​of constant voltage supply on the clamps of the electric primer. And between the changes in voltage at the point of acceptance of the culprit, the voltage drop from the designated point to the electrical receiver is indicated in the power supply agreement.

Voltage level (KN) – voltage level at intervals ranging from up to several seconds.

Injections of voltage and pressure are applied to the pulsed nature of the combined active and reactive energy, which changes sharply: arc and induction furnaces; aparati elektrozvaryuvan; electric motors in starting modes, etc. CN is characterized by the following indicators:

Change the voltage dUt with a sweep;

Flicker dose Pt.

Flicker – This is a subjective reaction to the human vibration of the light flow of piece lighting fixtures, like the surges of voltage in the electrical circuit, which is how to live with the fixture.

Flicker dose - the world of people's friendliness to the day of flicker for a period of time. Flicker nap time - Minimum amount of time for subjective acceptance by a person of a flicker evoked by the vibrations of tension in a singing form.

A short-term dose of flicker is administered at an interval of one hour of caution, which does not exceed 10 times. Trival dose of flicker is administered at an interval of one hour of observation, which is equal to 2 years.

Voltage non-sinusoidality is the creation of a sinusoidal shape of the voltage curve.

Electrical devices with a non-linear current-voltage characteristic resemble a strum, the shape of the curve varies from sinusoidal. And the passage of such a current by the elements of the electrical circuit creates a voltage drop on them, instead of the sinusoidal one. This is the reason for the curvature of the sinusoidal shape of the voltage curve.

Rice. 2.1. Non-sinusoidal voltage

The sinusoidal voltage is characterized by the following indicators:

The coefficient of curvature of the sinusoidality of the voltage curve is K U;

Coefficient of the n-th harmonic storage voltage U (n).

Voltage asymmetry - asymmetry of the three-phase voltage system.

Voltage asymmetry occurs only in a three-phase cycle under the influence of an uneven distribution of voltage across its phases. How to reliably drink wine in non-symmetrical tension GOST 13109 - 97 indicates a person with non-symmetrical pressure.

Unbalanced voltage devices: arc steel-smelting furnaces, traction substations of alternating jets, electromagnetic machines, single-phase electrothermal installations and other single-phase, two-phase and asymmetrical three-phase units and electricity, for the time being.

Thus, the total demand for other enterprises accounts for 85...90% of the asymmetrical gain. And the coefficient of voltage unbalance beyond the zero sequence (Up to 0U) of one 9-surface unit can be 20%, which on the busbars of the transformer substation (the point of the terminal connection) can exceed the permissible 2%.

Rice. 2.2. Voltage imbalance

Voltage asymmetry is characterized by the following indicators:

Voltage unbalance factor in the return sequence Up to 2U;

The voltage unbalance factor beyond the zero sequence is 0U.

Frequency variation – variation of the actual frequency of the alternating voltage (f fact) from the nominal value (f nom) in the stationary mode of operation of the electrical supply system.

The frequency variation of the alternating current in electrical circuits is characterized by the frequency variation indicator (f.

Voltage dip - rapt and voltage reduction values ​​(less than 90% U nom) trivial for several periods to several tens of seconds with further voltage increases.

The causes of voltage failures include the design of automatic protection systems when lightning overvoltages are turned on, short-circuit currents (SC), as well as during emergency protection or emergency actions for operating personnel.

GOST 13109-97 does not standardize voltage failure; it limits it to 30 seconds. However, there is practically no loss of voltage within 30 seconds - the voltage does not reappear.

The voltage failure is characterized by the voltage failure indicator Dtn. .

Voltage impulse - a sudden increase in voltage lasting less than 10 milliseconds.

Pulse overvoltages occur during lightning events and during equipment switching (transformers, motors, capacitors, cables), or during short-circuit circuits when switched on. The magnitude of the overvoltage impulse can reach many hundreds of thousands of volts.

GOST 13109-97 determines the correct values ​​of the pulse overvoltage during switching of various types of circuits.

Fig.2.3. Voltage impulse

The voltage pulse is characterized by the pulse voltage indicator U imp.

Time-hour overvoltage - rapt and voltage displacement value (more than 110% U nom) with a duration of more than 10 milliseconds.

Time-hour overvoltages occur during equipment switching (commutation, short-hour) and during short ground faults (tripals).

Commutation overvoltages occur when long high-voltage power lines are depleted. Overvoltage trivals occur in circuits with a compensated neutral, in parallel conductive circuits when the neutral wire is damaged, and in circuits with an insulated neutral in case of a single-phase short circuit to ground (for circuits of 6-10-35 kV in this mode, a robot trip is allowed). In these surges of voltage from unstable phases, the main ground (phase voltage) can increase to the value of the interphase (line) voltage.

The time-hour overvoltage is characterized by the time-hour overvoltage coefficient Up to per.

The norms for PKI guidance are given in Table 2.1. Since the change in VN and the change in frequency is of a phased nature, then the results of GOST 13109-97 are expanded, which throughout the developmental period may have an integral reliability of at least 95%.

Table 2.1. – Norms of KE indicators and possible reasons for their decrease

Vipadkovi news

1.1.1 Method of transferring from one ore material to another

1. The volume of the deposit is covered, which is introduced with salvage materials before and after remixing.

2. A number of materials are insured for the purpose of saving a number of deposits that must be added to the tone of the chavun.

3. How do you change it? Sio 2і Cao from the mixture, then you will have to pay for the change in the output of slag, waste the waste and the coke.

Umovne assigned	Indicator KE, one vimiru	Normie KE GOST 13109-97		More obvious reason
		normally acceptable	marginally acceptable
Voltage recovery
δuy	Stike VN, %	±5	±10
Voltage voltage
δut	Voltage range, %	-	curve 1.2 in Fig. 2.1
	Flicker dose, visible. od.: short hours trivala
Voltage sinusoidality
Ku	Voltage sinusoidal curvature coefficient, %	following table 2.1.2	following table 2.1.2
Ku(n)	Coefficient n - th harmonic storage voltage, %	following table 2.1.3	following table 2.1.3
Voltage asymmetry in a three-phase system
Up to 2 u	Voltage asymmetry coefficient behind the turning sequence, %	2	4
Up to 0 u	Voltage asymmetry coefficient after zero sequence, %	2	4
Others
Df	Frequency variation, Hz	±0.2

Compliant with GOST 23875-88, the power of electrical energy refers to the level of availability of electrical energy parameters and their setting values.

The parameter refers to a value that characterizes the power of electrical energy (for example, voltage, frequency, voltage waveform, etc.).

The difference between the exact values ​​of the electrical energy parameter and its nominal and basic values ​​is called the variation of the electrical energy parameter. As a basic value of the parameter, it can be accepted in the middle of the working, rozrakhunkov, border or stipulated by the power supply agreement.

Voltage (frequency) change - this means voltage (frequency) change in the operating mode of the electrical system.

Stress relief is assessed in hundreds

Voltage fluctuation is a series of single voltage changes within an hour. The voltage level is characterized by the magnitude of the voltage change and the dose of flicker.

The voltage swing is the value equal to the difference between the highest and lowest voltage values ​​over a single hour interval in the operating mode of the engine, converting electrical energy or the electrical system once it has returned.

Flicker is a subjective response to the human disturbance of the light flow of piece lighting fixtures caused by voltage fluctuations in the electrical circuit.

The dose of flicker is the level of a person’s tolerance for injecting flicker over a period of time.

By overvoltage in the electrical system we mean the displacement of the voltage above the highest operating voltage set for the electrical system. Under the current overvoltage, it is understood that the voltage shift at the point of the electrical margin is greater than 1.1 U HOM , with a duration of more than 10 ms, which occurs in power supply systems during switching

and short flickering.

Voltage impulse - a sudden change in voltage at the point of the electrical boundary with further updates to the beginning or close to the next level in the range of an hour to a few milliseconds.

Voltage failure means the Rapt value of voltage reduction (less than 0.9 U NDM) The system has power supply with further updates every hour from ten milliseconds to several tens of seconds.

Compliant with GOST 13109-97, the normally permissible and limiting permissible values ​​of the voltage supply that are set at the source of electrical energy are equal to +5% and +10% of the rated voltage gi electrical circuit.

Between the voltage swings, which are allowed, lie depending on the frequency of repetition of the voltage for the ridge and for the voltage that shapes the meander, change at a frequency of up to 10% of the nominal.

Normally permissible and limiting permissible values ​​of frequency variation are equal to +0.2 and +0.4 Hz.

A voltage failure is characterized by an indication of the severity of the voltage failure. The maximum permissible value for voltage failure in electrical voltages up to and including 20 kV is 30 s.

Small 3.1 illustrates the steps involved in pointing them out.

Change the shape of the alternating voltage curve (struma) - change the shape of the alternating voltage curve (struma) as necessary.

The coefficient of the shape of the curve of the alternating voltage (struma) is the value that brings the current value of the periodic voltage (struma) to its average value (over the period).

For sinusoid
.

The amplitude coefficient of the alternating voltage curve (struma) is the value that corresponds to the maximum change behind the module during the period of the voltage value (struma) to the normal value of the periodic voltage (struma). (For sinusoid
).

The coefficient of saturation of the sinusoidality of the voltage curve (stroke) is one of the main indicators of the electrical energy capacity, which brings the current value of the sum of the greater harmonic storage to the current value mainly ї storage voltage (struma):

% ,

de n- Serial number of the harmonic storage voltage. Another indicator of nonsinusoidality is the coefficient n- harmonic storage voltage:

, %.

The values ​​of the coefficient of transformation of the sinusoidality of the voltage curve, which are normally allowed and marginally allowed, are added together at the points of connection to the electrical limits:

h U NOM = 0.38 kV - 8 і 12%, s U NOM = 6 -20 kV - 5 і 8%, s U NOM = 35 kV - 4 and 6% , h U NOM= 110 - 330 kV - 2 and 3%. .

To characterize the asymmetry, use the asymmetry coefficient behind the gate and zero sequences.

The unbalance coefficient according to the return sequence is given by the interphase voltages, the geometric sum of which is always equal to zero. Vintage, %,

, % ,

de U 2 , U 1 - warehouse gates and direct sequences when laid out using the method of symmetrical warehouse systems of interphase voltage.

The asymmetry coefficient for a zero sequence is calculated as

, % .

It is similar to the high-hundredth quality of warehouse zero and direct sequences when laid out using the method of symmetrical phase voltage warehouse systems. Moreover, it is clear that the relationship U 1 і U 1 F For interconnected systems, phase and interphase voltages have a simple look:

U 1 =
U 1 F .

The normally permissible and limiting permissible values ​​of the voltage asymmetry coefficient along the return sequence at the points of the external connection to the electrical level are equal to 2 and 4%.

The values ​​of the zero-sequence asymmetry coefficient, which are normally acceptable and marginally acceptable, at the points of initial connection to four-wire electrical lines with a rated voltage of 0.38 kV equal to the line 2 and 4%.

Warehouses of direct and zero sequences can be introduced using linear transformation based on matrix alignment:

,

de
,

;
; A 3 = 1;

A 4 = A; 1+ a+a 2 = 0.

Here
і
the rational designation of the phase voltage vectors and the voltages that enter up to the symmetrical systems of zero, direct and reversal sequences, then.

= =
.

This means that systems of phase quantities can be folded from systems of zero ( ,,), direct way to avoid the basic order of drawing phases ( ,A 2 ,A) and return sequences ( , A, A 2 ).

The basic design of the phases is shown in Fig. 3.2. The arrow indicates that after the achievement of a positive maximum voltage in phase A, a positive maximum occurs in phase A, and then in phase C. The order of phase voltage distribution in the same vector of phase voltages corresponds to the basic order of phase rotation .

In the text part of the electrical supply project, it is necessary to provide a description of electrical receivers from the assigned categories of electrical supply necessary for them and a description of the inputs to ensure this category.

Reliable electrical power supply.

All survivable electrical energy is divided into 3 categories of power supply reliability, up to a goal. 1.2 PUE.

First category- in normal modes, it is necessary to provide electricity from two independent, mutually redundant power supply units, and interruption of the current power supply in the event of a power supply failure from one of the power supply units may be allowed for an additional hour of automatic renewal lively (Div. is also a special category).

These categories of electrical power supply are specified in the regulatory documents of every skin-related type of object (formerly, spores, mechanism). The technical minds of the boundary organization determine the category of electrical supply that the boundary organization will ensure on its own side. According to local regulatory documents, which indicate the category of reliability of a particular type of electrical appliance, an alignment is carried out. Since the category of electrical power supply for specifications is lower than required in regulatory documents, it is necessary to ensure that the necessary category is ensured by installing additional electrical energy devices - rechargeable batteries, diesel generators.

This is due to the replacement of GOST 13109-97 with GOST 32144-2013. The norms of electrical energy in electrical power supply systems are based on GOST R 50571.5.52-2011 (MEK 60364-5-52:2009) Low-voltage electrical installations. Select and install electrical installation. The important factors for designers have changed in order to reduce voltage losses in electrical circuits, as well as to reduce voltage losses.

Let’s look at paragraph 3 of the Explanatory Note:

Install a fire alarm system, a fire warning system, anti-fire devices, VZP, emergency lighting has been upgraded to category I. Provided with an AVR, DBZ device

To ensure another category of reliability on the Maidan, the quarantine worker is being victorious single-transformer The substation will have two cables from the TP and DDU.

Electrical receivers of the first category in normal modes are required to provide electricity from two independent, mutually redundant power supply units, and to interrupt their power supply in the event of a power supply failure from one of the power supply units You may be allowed an additional hour of automatic renewal of life. In connection with this, the emergency lighting lamps are connected to the emergency lighting units. Also, emergency living units will be installed in microclimate control panels and alarm systems and fire warning systems.